This just adds -std=c++11 to the compiler flags and fixes the resulting errors/warnings.

Later CLs can fix things related to the LLVM 3.5 merge.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3930
R=jfb@chromium.org, kschimpf@google.com

Review URL: https://codereview.chromium.org/607443003